[nottrobin]

Do you mention the distinction between creation and discovery because it's a distinction in law? Cos it seems intuitively obvious to me that distinguishing between creation and discovery has no philosophical merit - creativity happens within many finite domains, the size of the problem domain really has little relevance to something's artistic value.

The exhausting of useful chords as you describe has both already happened and will never happen. There are countless songs already based on the most common chord progressions, but new ones will also continue to be found for the foreseeable future. We're nowhere near knowing the size of this domain.